It is an interesting phenomenon that the response of the left half of our political spectrum to criticism and argument is often to try to shut it down. Thus President Obama in his Sept. 9 speech to a joint session of Congress told us to stop "bickering," as if principled objections to major changes in public policy were just childish obstinacy, and chastised his critics for telling "lies," employing "scare tactics" and playing "games." Unlike his predecessor, he sought to use the prestige of his office to shut criticism down.